Note: A more recent version of these rules is available at the index page for this game. We are retaining this page for historical purposes , along with this pdf of these rules formatted as they appeared in Pyramid Primer #1 in 2012.
Perhaps the most popular pyramid game is Volcano, but it requires an odd set of pyramids. Caldera is very similar, but it uses 6 Rainbow Stashes. Capture the winning pieces by causing eruptions!

How to Play Caldera 

Designed by Kristin Looney

Introduction: This is a puzzle game inspired by the spewing eruptions of volcanoes. The setup leaves an empty space in the center of the board, akin to the caldera of a volcano.

Number of Players: 2 or 3

Equipment: 6 Rainbow Stashes, 5 x 5 grid

Setup: Begin by stacking all the red, yellow, green, and blue pyramids into single-color Nests (groups of Larges atop Mediums atop Smalls). Arrange these in a randomized way on the 5x5 grid, with the empty space being located in the center of the board. When randomizing the placement of the nests, avoid putting the same two colors any closer together than corner-to-corner (no direct side-by-side color matching). Place a small black piece onto each of the six red nests. (Set the other black pieces aside; they will not be used.)

Who Goes First: The player who has traveled the closest to molten lava goes first (and also gets to brag about the time they visited an active volcano). Or, use another method to select a start player.

Eruptions: The primary action of the game is called Erupting. The nests becomes mountain tops which explode, spewing molten rock in a specic direction. Shown here is a complete 4-stage eruption. All eruptions begin when a small black piece (called a Cap) is moved onto another stack (as shown in Stage 1 above). The pieces under the cap then “flow” out in the same direction, each new piece landing farther away than the piece before it, continuing until the pieces run out or there’s nowhere for the next piece to land, either because it would go off the edge of the board, or because there’s a cap in the way (since nothing can ever be placed on top of a cap).

The only direct actions the players take in this game is to move the caps around on top of the other colored pieces. Sometimes when you move a cap, one or more pieces beneath it will erupt (as shown in the previous section). But oftentimes you can move a cap such that no eruption occurs, in which case you get to move a cap again (either the same one or a different one). In this way, a player can make many moves in one turn, moving the caps around until an eruption occurs. Your turn ends as soon as one or more pieces erupt, no matter how many times you moved caps.

  • While caps cannot be stacked upon, all other types of stacking are allowed. This can create some strange-looking towers.
  • You can move any number of caps any number of times, as long as nothing erupts.
  • Your turn ends when you cause an eruption of any kind, even if you fail to capture any pieces.

Legal Moves: Pieces can be moved as follows:

  • Caps can be moved in any direction, including diagonally.
  • Erupting pieces are all moved in the same direction as the cap that triggered the flow.
  • Caps (and erupting pieces) can not be moved beyond the edge of the 5x5 grid.
  • Caps (and erupting pieces) can be moved into the empty space in the center of the board (which is called the Caldera).          
  • Yes, moving a cap out of an empty square results in no eruption, and you can keep going.
  • No piece can ever land on top of a cap.

Given these rules, many moves will cause no eruption because the erupting piece would either go off the board or land on a cap.

Capturing: The object of the game is to capture pieces, which is done by causing eruptions. Whenever an erupting piece lands upon a piece of its same size, you capture the erupting piece(s).

For example, if you move a cap such that the erupting large lands upon a large, and the medium further lands upon a medium, you would remove those two pieces from the board and set them in front of you.

Only the topmost piece can be matched by the erupting piece to make a capture.

Turn Summary: Move a cap. If this does NOT cause an eruption, move a cap again until it does. Then, collect captured pieces.

Goal: To win, you must collect three monochrome Trios, i.e. three sets of small, medium, and large pieces of a single color. (Extra pieces in your collection do not matter.) The order in which you capture the pieces in your collection does not matter. You can freely rearrange the pyramids you’ve collected into different groups as you build your sets.

Power Play Option: At any time before you cause an eruption, you may choose to give up one of the pieces you’d previously captured, and put it back onto the board. This is called a Power Play. Doing this allows the player to alter the landscape and thus enable captures not otherwise available.